In the present study intestinal delivery systems resistant to gastric juice, loaded with the probiotic bacteria Lactobacillus acidophilus LA14 and Bifidobacterium lactis BI07, were produced by the polyelectrolyte complexation. First, beads were prepared by the traditional extrusion method and nine formulations were developed using alginate as main carrier and the biopolymer, xanthan gum, as hydrophilic retardant polymer or the cellulose derivative, cellulose acetate phthalateDevelopment of microparticulate systems for intestinal delivery of Lactobacillus acidophilus and Bifidobacterium lactis.